基于遗传算法预测2D三向的蛋白质结构

本文基于范德华力势能预测2D三向的蛋白质结构。首先,将蛋白质结构预测这一生物问题转化为数学问题,并建立基于范德华力势能函数的数学模型。其次,使用遗传算法对数学模型进行求解,为了提高蛋白质结构预测效率,我们在标准遗传算法的基础上引入了调整算子这一概念,改进了遗传算法。最后,进行数值模拟实验。实验的结果表明范德华力势能函数模型是可行的,同时,和规范遗传算法相比,改进后的遗传算法能够较大幅度提高算法的搜索效率,并且遗传算法在蛋白质结构预测问题上有巨大潜力。     

骨髓基质干细胞移植改善慢性酒精中毒大鼠脑损害的相关机制研究

目的:探讨骨髓基质干细胞(bone marrow stormal cells, BMSCs)静脉移植对慢性酒精中毒大鼠脑保护作用的相关机制。方法:体外分离、培养、扩增SD大鼠BMSCs。成年雄性SD大鼠随机分为慢性酒精中毒组、BMSCs回输组、磷酸缓冲盐溶液(phosphate buffer saline,PBS)回输组和对照组,每组7只。前三组用酒精灌胃8周建立慢性酒精中毒动物模型,对照组不造模(给予蔗糖灌胃),BMSCs回输组和PBS回输组于造模7周时一次性经尾静脉回输BMSCs或PBS。免疫印迹法检测海马Bcl-2、Bax、NGF、BDNF以及信号转导分子p-Akt的表达;反转录PCR检测海马神经生长因子(nerve growth factor, NGF)和脑源性神经营养因子(brain derived neurotrophic factor, BDNF)。结果:BMSCs回输组海马抗凋亡蛋白Bcl-2表达高于其余三组(P0.05);促凋亡蛋白Bax表达低于慢性酒精中毒组(P0.01),与对照组无统计学差异(P=0.989)。BMSCs回输组鼠海马内NGF和BDNF m RNA和蛋白表达、p-Akt蛋白表达均高于其余三组(P0.05)。结论:静脉移植BMSCs能够明显改善慢性酒精中毒大鼠海马的细胞凋亡;其可能与自或旁分泌BDNF和NGF营养因子有关,且可能部分是通过激活PI3K/Akt通路实现。     

肿瘤患者经外周放置中心静脉导管相关性感染的病原菌分布、耐药性及影响因素分析

目的:研究肿瘤患者经外周放置中心静脉导管(PICC)相关性感染的病原菌分布、耐药性,并分析其影响因素。方法:以2016年1月～2019年3月于我院行PICC置管的肿瘤化疗患者450例为研究对象,分析其PICC相关性感染发生情况。采集感染患者标本进行病原学检查,并分析感染病原菌种类、分布情况以及耐药性。同时对PICC相关性感染的影响因素进行分析。结果:450例患者发生PICC相关性感染的人数为40例,占比8.89%。共检出病原菌40株,其中革兰阳性球菌12株,革兰阴性杆菌28株。革兰阳性球菌对万古霉素、利奈唑胺和呋喃妥因均不耐药(0.00%),而对青霉素耐药率最高(100.00%)。鲍曼不动杆菌、铜绿假单胞菌对头孢吡肟、四环素的耐药率最高(100.00%),而鲍曼不动杆菌、铜绿假单胞菌和洋葱伯克霍尔德菌对呋喃妥因、头孢唑林的耐药率最低(0.00%)。经单因素分析发现:穿刺次数、导管留置时间、免疫功能、化疗次数以及是否合并糖尿病均与肿瘤患者PICC相关性感染有关(均P0.05)。经多因素Logistic回归分析显示:穿刺次数≥2次、免疫功能低下、化疗次数≥5次以及合并糖尿病均是肿瘤患者PICC相关性感染的独立危险因素(均P0.05)。结论:PICC相关性感染病原菌分布主要包括革兰阳性球菌与革兰阴性杆菌,临床应针对各病原菌的耐药性合理选择抗菌药物,同时加强对危险因素的干预,以降低PICC相关性感染的发生率。     

脾动脉介入栓塞治疗外伤性脾破裂的临床效果及对患者免疫功能的影响

目的:探讨脾动脉介入栓塞治疗外伤性脾破裂的临床效果及对患者免疫功能的影响。方法:选择2013年4月到2017年2月在中国人民解放军第九七医院进行急诊治疗的116例外伤性脾破裂患者,根据治疗方法的不同将其分为观察组60例与对照组56例,对照组接受脾脏切除手术,观察组给予脾动脉介入栓塞治疗,记录和比较两组的术后下床活动时间、术后住院时间、术后肛门排便时间、术后肛门排气时间、术中输血量、手术时间与治疗前后CD4~+/CD8~+、CD8~+、CD4~+、CD3~+的变化及不良反应的发生情况。结果:所有患者都完成治疗并抢救成功,观察组的术后下床活动时间、术后住院时间、术后肛门排便时间、术后肛门排气时间、术中输血量、手术时间都少于对照组(P0.05)。观察组围手术期间的急性肠梗阻、急性胰腺炎、肺炎等并发症发生率为3.33%,对照组为17.86%,观察组低于对照组(P0.05)。术后14天,两组白细胞与血小板含量均显著高于术前1天(P0.05),而观察组血小板含量显著低于对照组(P0.05),但两组白细胞含量比较差异无统计学意义(P0.05)。观察组术后14天与术后1个月的CD4+/CD8+、CD4+、CD3+值均明显高于对照组(P0.05),两组CD8+对比差异无统计学意义(P0.05)。结论:脾动脉介入栓塞治疗外伤性脾破裂能提高治疗的临床效果,减少术后并发症的发生,促进患者免疫功能的恢复。     

Generation and characterization of Brassica rapa ssp. pekinensis – B. oleracea var. capitata monosomic and disomic alien addition lines

Journal of Genetics - Five monosomic alien addition lines (MAALs) of Brassica rapa ssp. pekinensis – B. oleracea var. capitata were obtained by hybridization and backcrossing between B. rapa...     

Role of H2O2 dynamics in brassinosteroid‐induced stomatal closure and opening in Solanum lycopersicum

Brassinosteroids (BRs) are essential for plant growth and development; however, their roles in the regulation of stomatal opening or closure remain obscure. Here, the mechanism underlying BR‐induced stomatal movements is studied. The effects of 24‐epibrassinolide (EBR) on the stomatal apertures of tomato (Solanum lycopersicum) were measured by light microscopy using epidermal strips of wild type (WT), the abscisic acid (ABA)‐deficient notabilis (not) mutant, and plants silenced for SlBRI1, SlRBOH1 and SlGSH1. EBR induced stomatal opening within an appropriate range of concentrations, whereas high concentrations of EBR induced stomatal closure. EBR‐induced stomatal movements were closely related to dynamic changes in H₂O₂ and redox status in guard cells. The stomata of SlRBOH1‐silenced plants showed a significant loss of sensitivity to EBR. However, ABA deficiency abolished EBR‐induced stomatal closure but did not affect EBR‐induced stomatal opening. Silencing of SlGSH1, the critical gene involved in glutathione biosynthesis, disrupted glutathione redox homeostasis and abolished EBR‐induced stomatal opening. The results suggest that transient H₂O₂ production is essential for poising the cellular redox status of glutathione, which plays an important role in BR‐induced stomatal opening. However, a prolonged increase in H₂O₂ facilitated ABA signalling and stomatal closure.     

Influence of dominance rank and affiliation relationships on selfdirected behavior in female Tibetan macaques (Macaca thibetana)

Self-directed behavior(SDB) is characterized as an indicator of anxiety, frustration and stress in nonhuman primates. In this study, we collected self-directed behavior data from one group of free-ranging Tibetan macaques(Macaca thibetana) at Mt. Huangshan, China(September 2012–May 2013) using a combination of behavioral sampling methods including focal animal sampling, behavioral sampling, continuous sampling and instantaneous sampling. Our results showed that females engaged in significantly higher rates of self-directed behavior when they were in proximity to dominant individuals compared to subordinate ones. Conflict losers significantly increased their SDB rates after agonistic episodes, indicating that SDB might also serve as an index of anxiety in M. thibetana. We further found that females significantly increased their SDB rates when focal individual was proximity to weakly affiliation relationship higher rank members than to strongly affiliation relationship higher rank members. If conflicts were not reconciled, the postconflict SDB rates of losers were higher when they stayed with strongly affiliation opponents; if conflicts were reconciled, victims of strongly affiliation relationships opponents engaged in more SDB rates before reconciliation than after reconciliation, while victims of moderately affiliation relationships opponents did not engaged in more SDB rates before reconciliation than after reconciliation. We conclude that both of dominance rank and affiliation relationships might both influence the SDB rates of female Tibetan macaques significantly, suggesting that SDB is not only an index of anxiety in Tibetan macaques, but also can provide a new insight into evaluation of social relationships between individuals.     

人工海水胁迫下小麦芽期和苗期的耐盐性鉴定方法

本文采用不同浓度人工海水分别在小麦芽期和苗期进行胁迫处理,筛选不同时期、不同耐盐指标的适合处理浓度,并利用模糊数学隶属函数法计算各指标的隶属值,通过比较芽期、苗期各指标隶属值总平均值的大小来确定小麦品种耐盐性的强弱。建立了65%人工海水相对发芽率与40%人工海水相对芽长两指标相结合的小麦芽期耐盐性鉴定方法;以及在40%人工海水处理下综合株高增长量、根长增长量、地上部干重与地下部干重4个指标相对值的小麦苗期耐盐性鉴定方法。运用这两个鉴定方法可以有效地区分16个小麦品种在人工海水胁迫下的耐盐性差异。     

渔山列岛浮游动物的群落结构特征分析

2011年10月—2012年7月对渔山列岛浮游动物的种类组成、优势种、群落结构、丰度和生物量进行了调查,分析了浮游动物丰度、多样性指数及其与环境因子的相关性。调查共鉴定浮游动物8类45种,其中原生动物类14种,占31．1％;桡足类次之13种,占28．9％。主要优势种有中华哲水蚤（Calanussinicus）、根状拟铃虫（Tintin—nopsisradix）和桡足类幼虫（Copepoditenauplinua）。多样性指数（H＇）7月（3．324）最高,10月（2．988）最低。结合多样性指数及丰富度指数可见,调查期间渔山列岛浮游动物的生物多样性7月最高,物种较丰富。相关性分析表明,浮游动物群落分布与营养盐、水温、盐度等环境因子存在一定的相关性。     

1990—2011年三峡库区生态系统服务价值演变及驱动力

作为我国西南部重要的生态屏障和生态走廊,三峡库区具有重要的战略意义,其生态问题非常值得关注。研究以覆盖三峡库区的4期Landsat TM遥感影像为数据源,通过人机交互解译分别获得1990、1998、2006、2011年的土地利用/覆盖,参照中国陆地生态系统单位面积生态服务价值当量表,采用研究区单位面积产量与全国农田粮食单位面积产量的比值作为地区修订系数,计算库区生态系统单位面积生态服务价值当量表,同时利用生物量对林地的生态系统服务价值作进一步的修订。然后结合土地利用结构和生态敏感性指数,定量分析土地利用变化引起的生态服系统务价值变化及其驱动因子。结果显示:1990—2011年间,三峡库区生态系统服务价值主要由林地支撑(占76.75%),其次是水域、耕地(共23.19%),草地的贡献率最小(0.22%),总生态系统服务价值从1990年的479.55亿元增加到2011年的680.83亿元;各项服务功能价值中,食物生产功能价值下降,其他各项功能价值上升,以土壤形成与保护功能上升幅度最大,达36.61亿元,其次是气体调节(33.10亿元);驱动力分析表明,库区生态系统服务价值变化的主要原因是人类活动,特别是自1998年实施退耕还林工程以来,各自然生态系统的面积发生较大变化,同时,自然生态系统的健康程度和社会政策对生态系统服务价值变化的影响也不忽可视。研究表明,加强林地、草地和水域等生态系统服价值高的土地利用/覆盖类型保护,是维持库区生态系统稳定性的有效措施。